I just bought a 92 civic hatch like two weeks ago. It is a fixer upper, but seems to mechanically be in decent shape. A little backround information on the civic is it does have a no brand intake, and some headers as well. 5 speed. When I bought it two weeks ago it drove home fine (and hour and a half drive). Then after those two weeks past, the climate began to change and become a little colder. this is when the problem began to occur. When the weather outside is warm, the car runs perfectly fine, but if it is cold outside, the car idles weird. I can be driving the car, and running perfectly, but then once i stop at a red light (while cold outside) the car idles really low. somtimes from 100-300 rpms. and every now and again if sitting at the stop light for a long time, it'll die out. I have never had my car die out while it is warm outside though. I am just looking for some help on this problem, if anyone has any ideas of what it could be, any tips would be helpful. I need to begin some trouble shooting before it begins to really start getting cold where I'm from (Southern California, Los Angeles area.)

 

Check for "ebay chip" in the IAT sensor wires and remove if present. Anytime there's an idling problem start by cleaning the IACV, also check that the radiator is completely full of coolant. This model has a Fast Idle Thermal Valve to boost idle when first started in cold (<60F) weather. The valve has no effect once engine is warmed up. The engine does warm up, right? Don't run with no thermostat and overcool it.

 

the car does warm up. I'm going to clean the IACV tomorrow and check my radiator to see if it is completely full of coolant or not, it should be because i just replaced my radiator and filled it up.